I can't seem to get any n64 game working with the latest MESS binaries. Would disabling the RSP DRC help? How do I do this in the code?

With a 32-bit build or a 64-bit build? At the very least, Bust-A-Move 2 and Super Mario 64 worked fine for me before I started pissing around with the video code. They actually ran pretty well on my new machine, too, the former averaging 120-150% depending on how many bubbles were on-screen, and the latter 40-60% depending on geometry load.

EDIT: @JD: btw, how much work would be needed to avoid PAL games to crash hard? if it's not too hard, could you put it somewhere in your todo list (otoh, if it would require a lot of efforts, please ignore the request and focus on more important aspects...)